The present invention is concerned with new compounds, and particularly those having a fused bicyclic ring substituted with an amidine moiety. These compounds are each potent inhibitors of Factor D of the alternate pathway of complement, C1s of the classical pathway of complement, Factors Xa, XIIa, VIIa and thrombin of the coagulation pathway, plasmin in the fibrinolytic pathway, and kallikrein and high molecular weight kininogen in the inflammatory pathways. These proteases, which have serine in their active site, are called serine proteases and they are pivotal to most of the processes of inflammation and coagulation. In fact, these various systems are interactive with one another and it is difficult to activate one pathway without it influencing the others (see Diagram 1).
Early in this century, it was noted that antibodies were not able to lyse bacteria by themselves. Factors were identified in serum which were required for the lysis of bacteria by antibodies. In 1989 Ehrlich and Morgenroth proposed the term xe2x80x9ccomplementsxe2x80x9d for these factors because they complemented the activity of antibodies.
For many years cytolysis was the only known function of complement. During the past twenty five years, data in animals, including man, have identified the considerable biological potential of the complement system. The complement system functions as a xe2x80x9ccascade.xe2x80x9d Namely, once an activator of the system converts a zymogen to an active enzyme, the activated enzyme then activates one or more proteins at the next stage, which in turn activates other zymogens. This can lead to profound biological effects, if the system is not controlled. Normally, well-defined regulatory (inhibitory) mechanisms are in place to regulate complement activation. However, in a host of pathophysiological conditions, inappropriate activation of the complement system occurs, and cell damage and cytolysis occur in major organ systems. Inappropriate complement activation has been identified in preclinical and clinical models of a host of inflammatory diseases, including autoimmune diseases such as inflammatory arthritis, cerebral and cardiac ischemic insult, and adult respiratory distress syndrome, as a major pathophysiological pathway.
The complement system is composed of 20 plasma proteins that interact in a cascading series of enzymatic activations and feedback loops and provides an important effector mechanism for the humoral immune system. Activation of the complement system leads to induction of the inflammatory process, stimulation of phagocytosis, chemotaxis of white blood cells, release of inflammatory mediators from mast cells, increasing blood vessel permeability and ultimately the lysis and cell death of cancer cells, bacteria, and viral-infected cells and neutralization of viruses.
Complement proteins are produced by most cells in the body on a continual basis, and circulate through the blood in a non-activated form. Activation can be initiated by two pathways: the xe2x80x9cclassicalxe2x80x9d pathway and the xe2x80x9calternativexe2x80x9d pathway. While both pathways end up with activation of the key component C3, each pathway plays a distinctive role in host defense. The components of each pathway participate in a cascade of limited proteolysis reactions, cleaving the inactive form of the next component into a minor fragment (which itself may have biological properties) and a major fragment that goes on to participate in the next reaction. The major fragments of the final five components form a xe2x80x9cmembrane attachment complexxe2x80x9d (MAC) that lyses cell membranes.
The complement system has profound biological effects other than cell lysis. Most immune system effector cells have surface receptors for complement fragments. The complement fragments C3a, C4a and C5a induce inflammation and smooth muscle contraction and vasodilation. The binding of C3a, C4a or C5a to receptors on mast cells and basophils promotes the secretion of histamine and other mediators of inflammation. C5a also induces production of leukotrienes and affects neutrophils and monocytes in a variety of ways: increases adherence to endothelial cells, causes these cells to migrate toward the source of C5a, increases oxygen consumption and generation of free radicals and induces secretion of glycolytic and proteolytic enzymes. C5a also induces production of IL-1 by macrophages. C3a induces the release of granulocytes from bone marrow, leading to leukocytosis.
C3b and C4b act as opsonins, coating invading bacteria, parasites or other cells at the site of complement activation. This coating provides a recognition signal for phagocytic cells which then bind to and engulf the invading cells. Neutrophils, monocytes and eosinophils all have C3b receptors.
There are two mechanisms principally responsible for the inflammatory response and tissue destruction in autoimmune disease. In the first mechanisms, circulating autoantibodies bind to tissues carrying the antigen. The antigen-antibody complex on the tissue surface then triggers the classical pathway of complement and activates immune system cells that have Fc receptors. This in turn leads to cell lysis.
A second mechanism involves circulating immune complexes in the blood or intracellular fluids. The immune complexes are deposited in the kidneys, lungs, blood vessels and joints where they activate the complement cascade. Complement activation then leads to tissue destruction. This mechanism account for many of the serious complications of rheumatoid arthritis, systemic lupus, myasthenia gravis and autoimmune hemolytic anemia. In these diseases, immune complexes are continually being deposited and complement destruction of tissue is chronic. When the complexes deposit in joints, inflammation results and when they deposit in the kidney glomeruli complement activation destroys renal function.
Complement Factor D is a crucial enzyme in the alternative pathway of complement (see Volanakis, J. E., The complement system, In Clinical Rheumatology; Boll, G.; Koopman, W., Eds., W. B. Saunders: New York, 1986, pp. 21-27 and Volanakis, J. E., Narayana, S. V. L. Complement Factor D, a novel serine protease, Protein Sci. 1996, 5, p.553-564). Complement Factor D is essential for the formation and function of the C3- and C5-convertase of the alternative pathway of complement. Factor D is an enzyme necessary for the cleavage of C3b -bound factor B. It is a single polypeptide chain serine proteinase of Mr, 24,000. Human Factor D isolated from serum of normal individuals or from urine of patients with Fanconi""s syndrome exhibits esterolytic activity against peptide thioester substrates.
The low esterolytic activity of purified Factor D is compatible with the apparent absence of a structural zymogen for the enzyme in blood. That xe2x80x9cnativexe2x80x9d factor D in blood is in enzymatically active form was demonstrated by Lesavre and Muller-Eberhard, Mechanism of Action of Factor D of the Alternate Complement Pathway, J. Exp. Med., 148:1498-1509, 1978. They showed that distribution of Factor D hemolytic activity always overlapped that of antigenically measured Factor D protein when plasma or serum were subjected to various separation procedures. In addition, it has been shown that Factor D in serum can be inactivated by diisopropyl fluorophosphate and also by a series of serine proteinase inhibitors derived from isocoumarin. Inhibition of Factor D by these inhibitors results in inhibition of the alternative pathway indicating that no other proteinase can substitute for Factor D. Factor D was also shown to be synthesized and secreted in hemolytically active form by U937 cells, human blood-derived macrophages and HepG2 cells.
The serum concentration of Factor D, 1.8xc2x10.4 ug/mL is the lowest of any complement protein. Studies on patients with renal insufficiency and in vivo microperfusion experiments using rat kidneys have indicated that the low concentration of Factor D is maintained by an extremely rapid catabolic rate. Due to its small size, Factor D is filtered through the glomerular membrane and is catabolized by the proximal renal tubules. Low serum levels of the enzyme may contribute to the regulation of its activity. In fact, Factor D has been shown to be the limiting enzyme in the activation sequence of the alternative pathway.
Factor D belongs to the serine protease family of enzymes. Some of the other members of this family include trypsin, thrombin, factor Xa, factor XIIa, plasmin, kallilcrein and elastase. Factor D has extensive sequence and structural homology with these enzymes. In spite of the similarities, most of the general serine protease inhibitors do not inhibit Factor D.
There are suggestions of certain amidino compounds being serine protease inhibitors (see U.S. Pat. No. 4,454,338 to Fujii et al; U.S. Pat. No. 4,490,388 to Fujii et al. and U.S. Pat. No. 4,634,783 to Fujii et al.; French Patent No. 2500826 to Fujii et al.; Yaegashi et al., Synthesis and structure-activity of protease inhibitors. III. Amidinophenols and their benzoyl esters. Chem. Phamr. Bull., 1984, Volume 32 (11), pp.4466-4476; and Aoyama et al., Synthesis and structure-activity study of protease inhibitors. IV. Amidinonaphthols and related acyl derivatives. Chem. Pharm. Bull. 1985, Volume 33, pp. 1458-1471).
However, although some of these compounds have weak activity against Factor D, none are known to exhibit a strong inhibiting action against Factor D, and are not useful in suppressing alternate pathway activity. However, a potent inhibitor of Factor D would modulate the activation of the alternative pathway of the complement system.
It would therefore be desirable to identify serine protease inhibitors that are not only potent against enzymes in the coagulation, kinin and classical complement pathways, but also potent against Factor D of the alternate complement pathway. Although there have been various efforts to pharmacologically manipulate complement activation, to date there are no potent, useful inhibitors of Factor D reported.
The natural serine protease inhibitor, aprotinin, is currently in use in cardiovascular bypass graft surgery and its effectiveness in inhibiting plasmin has resulted in dramatic reduction in the need for transfusion. Such reported reductions have ranged between 35 and 90%. A synthetic serine protease inhibitor, nafamostat, has been shown to have similar good effect on plasmin in reducing transfusion requirements in patients having primary surgery in conjunction with heparin therapy as, for example, in cardiac bypass grafting. Several excellent inhibitors for thrombin, also a serine protease, have been developed to act as a specific inhibitor in the coagulation process. A recent one, novastan, is particularly useful as a replacement for heparin in surgery when patients have heparin-induced thrombocytopenia and other medical complications.
For many years, a search has been under way for the appropriate compound or xe2x80x9ccocktailxe2x80x9d of compounds, that could act during cardiopulmonary bypass as 1) an anticoagulant with the potency of heparin, 2) as inhibitor of the complement pathway, 3) an inhibitor of the kallikrein pathways, and 4) to inhibit plasmin and therefore prevent fibrinolysis of clots in microvessels. These processes would decrease organ injury due to blood activation on contact with the foreign surfaces of the pump oxygenator system.
Since these pathways are linked and interwined, it is clear that clinical conditions that are involved in their general activation, such as cardiopulmonary bypass systems, hemodialysis, hemofiltration, acute respiratory distress syndrome, septic shock, and disseminated intravascular coagulation will have many of the key serine proteases activated, which in turn perpetuates the further activation of the interlocking coagulation and inflammatory systems. In addition, diseases that are primarily mediated through the complement system potentially could be treated is acutely with an inhibitor of the classic and/or alternative pathways. These would include hereditary angio-edema and all immune complex diseases, such as lupus nephritis and many of the most difficult to treat vasculopathies and autoimmune diseases. Since serine proteases are active in several steps in the coagulation pathway, appropriate inhibitors should be highly-effective short-term anticoagulants. Because of an effect on the inflammatory pathways, prevention of reperfusion injury and perhaps acute tissue injury, such as in myocardial infarction, might be effectively treated in the acute stage by serine protease inhibitors.
The present invention provides novel compounds that possess the ability to inhibit the various pathways discussed above in the sub-micromolar range, some at an IC50 level of one nanomolar. This broad spectrum of inhibition of plasma serine proteases by compounds of the present invention is shown in the Table of the biological results disclosed elsewhere in this application.
The concept of xe2x80x9cblood anesthesiaxe2x80x9d has been introduced by cardiovascular surgeons working in the field of cardiopulmonary bypass. This term is applied to the use of combinations of compounds such as heparin, aprotinin, salicylates, persantin, etc. that could inhibit the coagulation components at several levels. The unexpected novelty of the compounds of the present invention, however, is that a single compound, highly specific for serine proteases, can act at multiple sites and singularly induce xe2x80x9cblood anesthesia.xe2x80x9d Thus, in this invention, novel compounds and especially amidine compounds are disclosed, each of which have potency in all of these interrelated pathways, and therefore form an ideal basis for acute therapy.
The concept of a single compound able to affect so many sites in the coagulation, complement, fibronilytic and inflammatory response systems is unique. No one has previously published that a compound which inhibits a broad spectrum of serine proteases could be useful. All other previous work has attempted to find a specific inhibitor of one enzyme. Nevertheless, Gorman, III, J. H.; Edmunds, Jr., L. H. Blood anesthesia for cardiopulmonary bypass. J. Card. Surg. 1995, 10, 270-279; and Royston, D. Preventing the inflammatory response to open-heart surgery: The role of aprotinin and other protease inhibitors. Int. J. Cardiol. 1996, 53 (suppl.), S11-S37 point out that a compound which could prevent all these blood proteases from being released would be clinically useful.
The compounds of the present invention contain four fragments, designated as L, E, R and Q, which are joined in a linear fashion as illustrated
Lxe2x80x94Exe2x80x94Rxe2x80x94Q
wherein:
Fragment L represents a hydrophobic group such as a 5-membered unsaturated ring, 6-membered unsaturated ring, alkene, saturated 3-7 membered ring;
Fragment E represents carbonyl derivative that in the presence of L, R and Q becomes an activated serine trap;
Fragment R represents a hydrophobic, aromatic ring system such as a 6-membered ring, fused 5-6 membered ring, or fused 6xe2x80x946 membered ring; and
Fragment Q represents a basic group. The present invention is also concerned with pharmaceutically acceptable acid addition salts of the above amidine compound.
Another aspect of the present invention is concerned with preparing the above-disclosed compounds. The process includes reacting a carboxylic acid with a substituted carbodiimide to produce a mixed anhydride. The mixed anhydride is then reacted with a phenolic compound or acid salt thereof in a base to provide the desired compound.
The compounds of the present invention can also be prepared by reacting an acid halide with a phenolic compound or acid salt thereof which is suspended or dissolved in an organic solvent.
Other coupling methods can be employed to produce the amidine compounds of the present invention.
Still other objects and advantages of the present invention will become readily apparent by those skilled in the art from the following detailed description wherein it is shown and described only the preferred embodiments of the invention, simply by way of illustration of the best mode contemplated of carrying out the invention. As will be realized the invention is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, without departing from the invention. Accordingly, the description is to be regarded as illustrative in nature and not as restrictive.
The novel compounds of the present invention contain four fragments, designated as L, E, R and Q, which are joined in a linear fashion as illustrated.
Lxe2x80x94Exe2x80x94Rxe2x80x94Q
Fragment L represents a hydrophobic group such as a 5-membered unsaturated ring, 6-membered unsaturated ring, alkene, or saturated 3-7 membered rings. Examples of such are listed in Tables 1 and 1a and designated by numbers. These ring moieties can be hydrocarbon rings or heterocyclic rings containing one or more N, O and/or S atoms in the ring and more typically 1-3 heterocyclic atoms.
A represents H, straight or branched lower alkyl chain of 1-4 carbon atoms;
B represents H, CF3, halogen such as Cl, I, Br, and F, (CH2)mCO2H, (CH2)mCH2OH, (CH2)mNHA, alkyl, alkoxy, aryl, or heterocyclic, and m=0-5.
Fragment E represents a carbonyl derivative that in the presence of L, R and Q becomes an activated serine trap. Tables 2 and 2a provide disclosure of exemplary E fragments, where each fragment is identified by a number.
Fragment R represents a hydrophobic, aromatic ring system such as a 6-membered ring, fused 5-6 membered ring, or fused 6xe2x80x946 membered ring. Examples of such are disclosed in Table 3 and labeled with a number.
Fragment Q represents a basic group, examples of which are disclosed in Table 4 and designated by a number.
To facilitate a disclosure of and understanding of the present invention, a list of exemplary compounds can be constructed from the above named tables of fragments by exhaustive enumeration of all combinations of the fragments in accordance with the formula Lxe2x80x94Exe2x80x94Rxe2x80x94Q. A compound of such an enumeration is depicted by a number designating an L fragment from Table 1 or Table 1a. followed by a number for the E fragment from Table 2 or Table 2a, a number for the R fragment given in Table 3, and a number designating the Q fragment listed in Table 4 as in the following form:
Fragment L:Fragment E:Fragment R:Fragment Q
For example 2-Amidino-6-benzofuranyl 2-furanylcarboxylate from Example 1 is represented by the depiction 46:1:14:2.
Specifically, the complete set of exemplary compounds consists of the union of the sets P and S wherein P is the exhaustive combinatorial enumeration of fragments from Tables 1, 2, 3, and 4 and S is the exhaustive combinatorial enumeration of fragments from Tables 1a, 2a, 3, and 4. Selected samples of the exhaustive combinatorial enumeration from sets P and S are given in Tables 5 and 5a, respectively.
Each fragment in the Tables 1, 1a, 2, 2a, 3, and 4 includes designation of the location of attachment to the adjacent fragment. 
More typical compounds are of the form where E is either C(xe2x95x90O)O or C(xe2x95x90O)S and Q is C(xe2x95x90NH)NH2 which are represented by the following formula I: 
wherein G is O or S and pharmaceutically acceptable acid addition salts.
In the above formula I, {circle around (R)} is a fused bicyclic ring. The ring preferably includes a six-membered unsaturated ring fused to a 5- or 6-membered hydrocarbon ring or heterocyclic ring. The heterocyclic rings can contain 1-4 heteroatoms selected from the group of O, N, S and mixtures.
In addition, the hydrocarbon ring variety of the fused bicyclic ring can contain one or more pendant groups such as H, lower alkyl of 1-5 carbon atoms, CF3, or halogen such as Cl, F, I, or Br.
The 6-membered unsaturated ring can be benzene or can include one or two nitrogen atoms in the ring. Examples of more typical {circle around (R)} bicyclic ring varieties identified as group R1 are as follows: 
wherein each X, Y and Z individually is N or C(J2), and J2 is individually H, F, Cl, Br, I, CF3 or lower alkyl of 1-5 carbons.
J3 is H or a lower alkyl having 1-5 carbon atoms.
In the above formula I, L is an unsaturated aliphatic chain, a 2-, 3- or 4-substituted benzene ring, a cycloalkyl ring of 3-7 carbons, or a five or six-membered heterocyclic ring containing 1-4 heteratoms, preferably O, N or S. Mixtures of heteratoms can be employed when desired. Examples of more typical L groups, identified as group L1, are as follows: 
wherein each J1 is H, (CH2)mCO2H, (CH2)mCH2OH, (CH2)mCONH2, (CH2)mNHJ3, CF3, halogen such as Cl, Br, I, and F, alkyl, alkoxy, aryl or heterocyclic. J3 in the above formula is H, straight or branched lower alkyl of 1-4 carbon atoms, and m is an integer from 0 to 5. The alkyl group preferably contains 1-10 carbon atoms and more preferably 1-4 carbon atoms, examples of which are methyl, ethyl and propyl
The alkoxy groups preferably contain 1-10 carbon atoms and more preferably 1-3 carbon atoms, examples of which are methoxy and ethoxy.
The aryl groups preferably contain 6-14 carbon atoms, examples of which are phenyl, naphthyl and anthracyl, with phenyl being most preferred
The heterocyclic groups preferably contain 5 or 6 atoms in the ring, 1-4 being a heteroatom, such as N, S or O. Mixtures of heteroatoms can be used when desired. Examples of more typical five-membered rings are those disclosed above. Examples of some suitable six-membered heteroaromatic rings are 2-, 3- or 4-pyrazinyl, 2-, 3- or 4-pyrimidinyl, 2-, 3- or 4-pyridazinyl, 2-, 3- or 4-pyridinyl, 2- or 3-furanyl, and 2- or 3-thienyl.
L is preferably phenyl, 2- or 3-furanyl or 2- or 3-thienyl.
Examples of some compounds according to the present invention are represented by one of the following formulae II, III, IV, V, VI, VII, VIII, IX, X, XI, XII, or XIII. 
wherein
G is O or S;
L is selected from the group consisting of a
cycloalkyl ring of 3-7 carbon atoms,
alkene of 2-6 carbon atoms,
benzene ring,
5 membered unsubstituted or substituted aromatic heterocyclic ring, having one, two or three heteroatoms which are the same or different and which are selected from sulfur, oxygen and nitrogen, or
6 membered unsubstituted or substituted aromatic heterocyclic ring, having one, two, or three heteroatoms which are the same or different and which are selected from sulfur, oxygen and nitrogen
wherein each member of said group can have 0, 1, 2, or 3 pendant groups selected from the group J1;
wherein each J1 is individually selected from the group consisting of
H, halogen,
CF3,
alkyl group, straight or branched, of 1-5 carbon atoms,
alkoxy group having 1-5 carbon atoms,
aryl, and
heterocyclic.
Q1 is selected from NH2, C(xe2x95x90NH)NH2, NHC(xe2x95x90NH)NH2, or CH2NH2;
X1, X2 and X3 are independently C(J2) or N;
Y is C(J2) or N(J3);
Z1 is O, N or S;
Z2 is O, N, S, SO, SO2 or CO;
each J2 is individually selected from
H, halogen,
CF3 or,
lower alkyl, straight or branched, of 1-5 carbon atoms;
each J3 is individually selected from
H or,
lower alkyl, straight or branched, of 1-5 carbon atoms; and
pharmaceutically acceptable salts thereof.
Acids which can be used to prepare salts are pharmaceutically acceptable ones including inorganic acids such as hydrochloric acid, sulfuric acid and phosphoric acid and organic acids such as acetic acid, lactic acid, citric acid, methanesulfonic acid, succinic acid, fumaric acid and maleic acid.
The compounds of the present invention and their pharmaceutically acceptable acid addition salts are useful as anti-complement agents. They exhibit potent inhibiting action against Factor D of the alternate complement pathway and C1s of the classical complement pathway. In fact, they are more potent inhibitors of Factor D and C1s than prior art compounds, including those mentioned in U.S. Pat. No. 4,490,388 to Fujii et al.
The compounds also exhibit inhibitory activities against proteases, such as thrombin, Factor Xa, Factor XIIa, plasmin and kallikrein and thus would be useful for anticoagulation and antiplatelet activity. In addition, these compounds would be useful in reducing blood loss secondary to anticoagulation. Compounds of the present invention would be useful for inducing blood anesthesia.
The compounds of the present invention can be prepared by reacting a carboxylic acid with a substituted carbodiimide in the presence of a base such as pyridine, triethylamine or 4-dimethylaminopyridine to produce a mixed anhydride.
The mixed anhydride is then reacted with a phenolic compound or acid salt thereof in a base such as pyridine, triethylamine or 4-dimethylaminopyridine to provide the desired amidine compound. The reaction is preferably carried out at temperatures of from about 0xc2x0 C. to about 80xc2x0 C., preferably 0xc2x0 C.-10xc2x0 C., using stoichiometrical amounts of the reactants or up to about a 10% excess of one of the reactants.
The compounds of the present invention can also be prepared by reacting an acid halide with a phenolic compound or acid salt thereof which is suspended or dissolved in an organic solvent such as pyridine, dimethyl formamide or dimethyl sulfoxide. When the solvent such as dimethyl formamide or dimethyl sulfoxide is used, it is desirable to use a base such as pyridine, triethylamine or 4-dimethylaminopyridine to produce the desired amidine compound.
The compounds of the present invention can be administered by any conventional means available for use in conjunction with pharmaceuticals, either as individual therapeutic agents or in a combination of therapeutic agents. They can be administered alone, but generally administered with a pharmaceutical carrier selected on the basis of the chosen route of administration and standard pharmaceutical practice.
The dosage administered will, of course, vary depending upon known factors, such as the pharmacodynamic characteristics of the particular agent and its mode and route of administration; the age, health and weight of the recipient; the nature and extent of the symptoms, the kind of concurrent treatment; the frequency of treatment; and the effect desired. A daily dosage of active ingredient for mammals (including man) can be expected to be about 0.001 to 1000 milligram (mg) per kilogram (kg) of body weight, with the preferred dose being 0.1 to about 30 mg/kg.
Dosage forms (compositions suitable for administration) contain from about 1 mg to about 100 mg of active ingredient per unit. In these pharmaceutical compositions, the active ingredient will ordinarily be present in an amount of about 0.5-95% by weight based on the total weight of the composition.
The active ingredient can be administered orally in solid dosage forms, such as capsules, tablets and powders, or in liquid dosage forms, such as elixirs, syrups and suspensions. It can be formulated in a sterile liquid or as a sterile powder for parenteral use, to be administered parenterally, as a sterile liquid dosage form or controlled-release depot injection. The active ingredient can also be administered intranasally (nose drops) or by inhalation. Other dosage forms are potentially possible such as administration transdermally, via a patch mechanism, ointment or iontophoretic device. It can be administered into a body cavity, such as into the rectum, vagina, or urethea as a solution, semi-solid or solid.
Gelatin capsules contain the active ingredient and powdered carriers, such as lactose, starch, cellulose derivatives, magnesium stearate, stearic acid, and the like. Similar diluents can be used to make compressed tablets. Both tablets and capsules can be manufactured as sustained release products to provide for continuous release of medication over a period of hours. Compressed tablets can be sugar-coated or film-coated to mask any unpleasant taste and protect the tablet from the atmosphere, or enteric coated for selective disintegration in the gastrointestinal tract.
Liquid dosage forms for oral administration can contain coloring and flavoring to increase patient acceptance.
In general, water, a suitable oil, saline, aqueous dextrose (glucose) and related sugar solutions and glycols, such as propylene glycol or polyethylene glycols are suitable carriers for parenteral solutions. Solutions for parenteral administration preferably contain a water-soluble salt of the active ingredient, suitable stabilizing agents, complexing agents, chelating agents, sufactants, and if necessary, buffer substances. Antioxidizing agents such as sodium bisulfite, sodium sulfite or ascorbic acid, either alone or combined, are suitable stabilizing agents. Also used are citric acid and its salts and sodium EDTA. In addition, parenteral solutions can contain preservatives, such as benzalkonium chloride, methyl- or propylparaben, and chlorobutanol.
Suitable pharmaceutical carriers are described in Remington""s Pharmaceutical Sciences, Mack Publishing Company, a standard reference text in this field.
Examples of useful pharmaceutical dosage forms for administration of the compounds of this invention can be illustrated as follows:
Capsules
A large number of unit capsules are prepared by filling standard two-piece hard gelatin capsules each with 100 mg of powdered active ingredient, 150 mg of lactose, 50 mg of powdered cellulose, and 6 mg of magnesium stearate or colloidal silica.
Soft Gelatin Capsules
A mixture of active ingredient in a digestible oil such as soybean oil, cottonseed oil, or olive oil or a cosolvent mix containing one or more of PEG400, sorbitol, glycerol, propylene glycol is prepared and injected into thermo formed gelatin to form seam or seamless soft gelatin capsules or beads containing 100 mg of the active ingredient. The capsules are washed and dried.
Tablets
A large number of tablets are prepared by conventional procedures so that the dosage unit was 100 mg of active ingredient, 0.2 mg of colloidal silicon dioxide, 5 mg of magnesium stearate, 275 mg of microcrystalline cellulose, 11 mg of starch, and 98.8 mg of lactose. Appropriate coatings may be applied to increase palatability or delay absorption.
Moreover, the compounds of the present invention can be administered in the form of nose drops or a nasal inhaler.
Various modifications of the invention in addition to those shown and described herein will be apparent to those skilled in the art from the foregoing description. Such modifications are also intended to fall within the scope of the appended claims.
The foregoing disclosure includes all the information deemed essential to enable those skilled in the art to practice the claimed invention. Because the cited applications may provide further useful information, these cited materials are hereby incorporated by reference in their entirety.
The following non-limiting examples are presented to further facilitate an understanding of the present invention: